A day after issuing a warning not to travel to China, the United States further intensified its prevention of the spread of the Wuhan coronavirus and announced that it would prohibit entry to the country to any traveler who has been to China in the two weeks prior to his arrival. The maximum incubation time for the virus is 14 days. The measure, justified by a “public health emergency” will take effect on Sunday, February 2. Delta, American Airlines and United Arilines airlines announced the suspension of all their flights with China.

A few hours earlier, the Center for Disease Control (CDC) ordered a mandatory 14-day quarantine starting this Friday for the 195 Americans repatriated last Wednesday from the city of Wuhan, epicenter of the health crisis. The plane carrying the evacuees landed at the March military base in Riverside, California, and they were initially going to be in a voluntary 72-hour quarantine. Then, according to the initial plan, they could go home, where they would continue to be monitored.

“This is a precautionary and precautionary step to maximize containment of the virus for the health of the public,” the CDC said in a statement. As of Thursday, none of the passengers had shown symptoms of the disease, which are those of pneumonia, with cough, fever and respiratory difficulties. The last time the CDC imposed a general quarantine like this was 50 years ago during a smallpox outbreak.

Authorities insist that there is no health crisis in the United States, but they are preparing as if there were. “We are preparing as if this is the next pandemic, but we are hopeful that it is not and that this will not be the case,” said Dr. Nancy Messonnier, director of the National Center for Respiratory Diseases in the United States, on Friday. “While we recognize that it is an unprecedented action, we face an unprecedented public health threat.”

In the afternoon, the CDC confirmed the seventh known case of infection in the United States. This is a man who lives in San Francisco, California, and who had recently traveled to China. The first case in the United States of a patient who had contracted the virus without having traveled to China had been confirmed in Chicago on Thursday. This is the husband of a woman who had traveled to Wuhan.